JP5607162B2 - Optical fiber with multilayer coating system - Google Patents

Description

Explanation of related applications

  This application is a benefit of US Provisional Patent Application No. 61 / 233,273, filed on August 12, 2009, with the name “Optical Fiber Containing Multi-Layered Coating System”. File a patent application and claim its priority. The contents of the specification of this patent application are hereby incorporated by reference in their entirety.

  The present invention generally relates to an optical fiber coating system, an optical fiber having a coating system, and a method of making the same.

  Optical fibers generally have a glass core and at least two layers of coating, such as a primary (or inner layer) coating and a secondary (or outer layer) coating. The primary coating is applied directly to the glass fiber and, when cured, forms a soft, resilient and supple material that encapsulates the glass fiber. The primary coating not only serves as a buffer to buffer and protect the glass fiber core when the glass fiber is bent, braided or wound on a spool, but it is also the source of cracks that cause failure. It also protects the glass surface from water absorption, which can promote growth and increase static fatigue. The secondary coating is applied over the primary coating and serves as a tough protective outer layer that prevents damage to the glass fiber during processing and use.

  Several features are desirable for secondary coatings. Prior to curing, the secondary coating composition should have a suitable viscosity and should be able to cure rapidly to allow processing of the optical fiber. After curing, the secondary coating has the following characteristics: sufficient rigidity to protect the encapsulated glass fiber and at the same time sufficient flexibility for handling (for example, elastic modulus), low water absorption, low to allow handling of the optical fiber It should have stickiness, chemical resistance and sufficient adhesion to the primary coating.

Several features are desirable for the primary coating. Prior to curing, the primary coating composition should also have a suitable viscosity and be able to cure rapidly to allow processing of the optical fiber. After curing, the primary coating has a sufficiently low modulus to buffer and protect the fiber by easily releasing the stress on the fiber, which can induce microbending and thus reduce signal transmission efficiency. Must have. This buffering effect must be maintained over the lifetime of the fiber. Due to the different thermal expansion characteristics between the primary and secondary coatings, the primary coating must also have a glass transition temperature (T _g ) that is lower than the lowest predictable use temperature, so that the primary coating is used. It becomes possible to maintain elasticity over the temperature range. Finally, the primary coating has good glass adhesion, and at the same time it can be mechanically removed from individual fibers or from ribbons with a reasonable force leaving little (preferably no) residue. It is important to be.

  The above requirements place conflicting constraints on the coating, especially on the primary coating. For example, if the primary coating is soft and thick, the ribbon peelability and mechanical damage to the primary coating are worsened, but the microbending resistance is improved under the same conditions. If the coating is very soft, the protection against static fatigue is generally worse.

  To date, manufacturers have only provided coatings that are a compromise between these properties. In response to the need for coatings with higher microbending resistance for fibers in dense or very small cables, commercial coatings have become softer than coatings 10 years ago, during which time The basic two-layer structure of the coating has not changed. However, cable manufacturers continue to demand further improvements, and a two-layer composite structure can no longer be sufficient. Therefore, an optical fiber coating system that is superior to the performance achieved with conventional two-layer coating systems, improves anti-microbending performance, improves the failure rate due to fatigue, and at the same time maintains or improves the coating stripping performance It would be desirable to develop.

  The present invention is directed to overcoming these deficiencies of the prior art.

  The first aspect of the present invention relates to a glass fiber and an optical fiber having three or more layers encapsulating the glass fiber, wherein the three or more layers are a primary coating in contact with the glass fiber and a single layer surrounding the primary coating. Including the above intermediate coating and an outer coating surrounding one or more intermediate coatings. The optical fiber of the present invention preferably has an outer coating diameter (or cross-sectional dimension) of less than about 300 μm.

According to one preferred embodiment, the primary coating has a Young's modulus of about 0.025 to about 3 MPa, more preferably about 0.05 to about 3 MPa and / or a T of about −100 ° C. to about −25 ° C. has a _g, intermediate coating is the same or implement specific Young's modulus of the primary coating, or even lower, the Young's modulus and if a T _g substantially the same as that of the primary coating, or even a low T _g Either or both.

According to another preferred embodiment, the optical fiber has a coating of at least four layers encapsulating the glass fiber, the coating of at least four layers being a primary coating in contact with the glass fiber, a first coating surrounding the primary coating. A first intermediate coating, a second intermediate coating surrounding the first intermediate coating, and an outer coating surrounding the second intermediate coating. The first intermediate coating may have any one of a higher T _g than the Primary Coating Young's high Young's modulus than the modulus and primary coating of the glass transition temperature (T _g) or the second intermediate coating of the first intermediate coating also has an outer layer covering the Young's modulus higher than the Young's modulus of the second intermediate coating and a second intermediate coating one lower Young's modulus than the Young's modulus and either the first lower the T _g of the intermediate coating T _g or also one of a T _g higher than T _g also have any. The optical fiber of the present invention preferably has an outer coating diameter (or cross-sectional dimension) of less than about 300 μm.

As used herein, the Young's modulus of the cured primary coating material or the second intermediate coating material is calculated by Steeman et al., “Mechanical analysis of in situ primary coating modulus test of optical fiber elements. Analysis of the in-situ Primary Coating Modulus Test for Optical Fibers) ^{", Proc. of the 52 nd International} Wire and Cable Symposium (IWC basis), November 10-13, 2003, described the United States Philadelphia, p.41 Measured using a pull-out in-situ elastic modulus test. The elastic modulus of the cured first intermediate coating material or outer layer coating material can be determined by dynamic mechanical analysis at a frequency of 1 Hz or by three-point bending (after stripping the composite from the glass fiber) of the primary / secondary composite coating. Can be determined. Since the elastic modulus of the secondary coating is approximately three orders of magnitude higher than that of the primary coating, the contribution of the primary coating can be ignored. “Substantially the same” means that the Young's value of the cured product is not greater than about 20% higher or less than about 20% lower than the Young's modulus value of the cured product of an equivalent polymer material. More preferably not greater than about 17.5% higher or less than about 17.5 lower, most preferably not greater than about 15% higher or less than about 15% lower. Means no.

As used herein, the glass transition temperature (T _g ) of a coating material is the temperature point at which its coefficient of thermal expansion changes abruptly (ie, the loss tangent (tan δ) as a function of temperature is maximized). Point to. T _g material is brittle at lower temperatures, the material at a temperature higher the T _g is flexible. T _g can be determined by dynamic mechanical analysis at a frequency of 1 Hz. “Substantially the same” means that the T _g is not higher than about 10 ° C. higher or lower than about 10 ° C. below the T _g measurement of an equivalent polymeric material, more preferably about 5 It means not higher than a high temperature or lower than a temperature lower than about 5 ° C., most preferably not higher than a temperature higher than about 2 ° C. or lower than a temperature lower than about 2 ° C.

  A second aspect of the present invention relates to an optical fiber ribbon or optical fiber bundle having a plurality of optical fibers according to the first aspect of the present invention and a matrix material encapsulating the plurality of optical fibers.

  A third aspect of the invention relates to a telecommunications system comprising an optical fiber according to the first aspect of the invention or an optical fiber ribbon or optical fiber bundle according to the second aspect of the invention.

  A fourth aspect of the present invention relates to a method for manufacturing an optical fiber according to the first aspect of the present invention. The method includes coating an optical fiber with three or more polymerizable compositions, and polymerizing the three or more polymerizable compositions, thereby forming three or more layers of encapsulating glass fibers. Therefore, the process of producing an optical fiber is included.

  A number of advantages are obtained by the construction of the optical fiber coating according to the present invention. One important advantage is that the innermost (primary) and outermost (secondary) coatings often contain expensive additives, or even major components, to control their properties. It can be adjusted to reduce the consumption of such additives / components per unit length. For example, the amount of glass fixer and surfactant used per unit length of fiber can be reduced by controlling the size of the innermost layer coating, and the unit length of the fiber by controlling the size of the outermost layer coating. The amount of the tackifier, lubricant, slip agent, wax, and additive (fluorescent agent) that improves the photon capture efficiency can be reduced. Furthermore, the use of less oligomers or photoinitiators in one or more of the intermediate coatings should also reduce the total oligomer or photoinitiator content per unit length of fiber. Finally, in some embodiments of the present invention, three or more layers of coatings can have a reduced total thickness compared to the coating systems available for commercially available fibers available today. All of these changes should allow for significant cost savings. As an example, fixers are often expensive—adding as much as 20% to the cost of coating—but offer little benefit to the bulk properties of the coating. Thus, by reducing the size of the primary coating, the overall cost of the fixer can be reduced to less than 10%, even more preferably less than 5% of the total cost of the coating.

Another important advantage is that the properties of the innermost (primary) coating and the outermost coating can function without interference due to undesired interactions between these coatings as would occur in conventional two-layer configurations. It can be improved about. For example, in a two-layer configuration, the elastic modulus and T _g of the secondary coating will be limited because it may pull the primary coating away from the glass (Aloisio et al., “Optical fiber coating separation using model coating materials. Layer (Optical Fiber Coating Delamination Using Model Coating Materials), Proc. Of the 51 ^st International Wire and Cable Symposium, 2002, p.738-747; elastic analysis (a Viscoelastic analysis of Thermally Induced Residual Stresses in Dual Coated Optical Fibers) ^{", Proceedings 44 th International Wire and Cable} Symposium, 1995 years, p.139~145. herein is the entire each of each of these documents Included as a reference). However, in the multilayer structure of the present invention, these two coatings are no longer in direct contact, thus increasing the flexibility in selecting the respective properties. As a result, it is possible to employ an outer layer coating having a considerably high elastic modulus. Finally, with respect to four layers (or more) configuration, the presence of the elastic modulus and T _g is relatively high first intermediate coating, even when the outer secondary coating is damaged, some protection against fiber Is provided.

  Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art, including the following detailed description and the appended claims, It will be appreciated by practice as described herein, including the attached drawings.

  Both the foregoing general description and the following detailed description are exemplary only, and are intended to provide an overview or framework for understanding the nature and nature of the invention as claimed. It is natural. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operations of the invention.

FIG. 1 is a cross-sectional view of a four-layer coating on an optical fiber according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a three-layer coating on an optical fiber according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of an optical fiber ribbon of the present invention having one or more optical fibers of the present invention. FIG. 4 is a schematic diagram of a process for drawing and coating an optical fiber having a four-layer coating system. FIG. 5 is a graph showing predicted relative core displacement for an optical fiber having a four-layer coating system versus predicted relative core displacement for two commercially available compliant optical fibers G652. Core displacement can be reduced in a four-layer coating system when the second intermediate coating layer begins approximately 190 μm from the core center. This indicates that the four-layer coating should be superior to the two-layer coating in microbending performance because the second intermediate layer can be made much softer than the primary coating in the two-layer coating type. FIG. 6 is a graph showing the microbending performance of the test fiber 1 by attenuation loss at 1310 nm, 1550 nm and 1625 nm during a temperature cycle of −60 to 70 ° C. FIG. 7 is a graph showing the microbending performance of test fiber 2 by attenuation loss at 1310 nm, 1550 nm and 1625 nm during a temperature cycle of −60 to 70 ° C. FIG. 8 is a graph showing a predicted core displacement value based on a damping loss measured at a tension of 100 g in the wire mesh drum test. The calculated displacement is estimated based on the measured attenuation loss and the elastic modulus and thickness of each coating layer.

  The present invention relates to an optical fiber having three or more coatings encapsulating the fiber therein, and also relates to a method of manufacturing such an optical fiber and its use in a fiber optic ribbon / cable and telecommunications system.

  The optical fiber of the present invention has a coating of three or more layers enclosing the inner fiber. The three or more coatings include a primary coating in contact with the glass fiber, one or more intermediate coatings, and an outer coating. Due to the presence of one or more intermediate coatings, it is possible to better adjust the properties of the primary and outer coatings for their intended purpose without adversely affecting each other. These intermediate coatings provide improved overall microbending performance of the optical fiber with low attenuation loss.

  Referring initially to FIG. 1, an optical fiber 10 according to one embodiment of the present invention has a fiber 12 and four layers of coatings 14, 15, 16 and 18 that encapsulate the fiber 12. The fiber 12 preferably has a glass core. The coating 14 is the primary (innermost layer) coating and meets the conventional purpose of the primary coating as described above. The coating 18 is an outer coating and meets the conventional purpose of a secondary coating as described above. There is a first intermediate coating 15 and a second intermediate coating 16 between the primary coating and the secondary coating. The materials and compositions used to make these coatings are described below.

  The fiber 12 is generally formed of glass, primarily quartz glass, and has a glass coating, known as a glass core and cladding layer. Glass fibers can be formed according to many processes known in the art. In many applications, the glass core and the cladding layer have a distinct core / cladding boundary. Alternatively, there may be no clear boundary between the core and the cladding layer. One such glass fiber is a step index fiber. Examples of step index fibers are described in Chang US Pat. Nos. 4,300,030 and 4,402,570. Each of these specifications is included herein in its entirety. Another such fiber is a graded index fiber in which the refractive index varies with distance from the fiber center. A graded index fiber is basically formed by interdiffusion of a glass core and a cladding layer. Examples of graded index fiber include US Pat. No. 5,729,645 to Garito et al., US Pat. No. 4,439,008 to Joormann et al., US Pat. No. 4,176,911 to Marcatili et al., And DiMarcello. U.S. Pat. No. 4,076,380. Each of these specifications is included herein in its entirety. Glass fibers can also be single mode or multimode at important wavelengths, such as 1310 nm or 1550 nm. The optical fiber of the present invention may have any of the above or other conventional core / cladding layer configurations now known or later developed.

  The various coatings used in the optical fiber of the present invention generally crosslink during the curing process, except as noted below. These coatings can be formed with one or more oligomers or polymers, one or more monomers, a polymerization initiator (if desired), and optionally one or more additives.

  When present, the oligomer component is preferably an ethylenically unsaturated oligomer, more preferably a (meth) acrylate oligomer. “(Meth) acrylate” is intended to encompass both acrylates and methacrylates, and combinations thereof. The (meth) acrylate end groups in such oligomers may be provided in known manner by a monohydropoly (meth) acrylate capping component or by a mono (meth) acrylate capping component, such as 2-hydroxyethyl acrylate. it can.

  Urethane oligomers are conventionally obtained by reacting an aliphatic or aromatic diisocyanate with a dihydropolyether or dihydropolyester, most commonly a polyoxyalkylene glycol such as polyethylene glycol. Such oligomers generally have 4 to 10 urethane groups and can have a high molecular weight, for example 2000 to 80000. However, low molecular weight oligomers having a molecular weight in the range of 500 to 2000 can also be used. Such synthesis is described in detail in U.S. Pat. No. 4,608,409 to Coady et al. And U.S. Pat. No. 4,609,718 to Bishop et al. Each of these specifications is included herein by reference.

  Where the use of moisture resistant oligomers is desired, such oligomers are similar in that a polar polyether glycol or polar polyester glycol is avoided and a saturated dominant / nonpolar dominant aliphatic diol is selected instead. Can be synthesized. Such diols include, for example, alkene diols or alkylene diols having from 2 to 250 carbon atoms and preferably substantially free of ether or ester groups. The range of viscosity and molecular weight of the oligomers that can be obtained in these systems is similar to the properties that can be obtained in unsaturated / polar oligomer systems so that their viscosity and coating properties can be kept substantially unchanged. . It has been found that the reduced oxygen content of these coatings does not unacceptably reduce the adhesion properties of the coating to the surface of the coated glass fiber.

  As is well known, the polyurea component can be incorporated into the oligomers made by these methods by simply replacing the diol or polyol with a diamine or polyamine during the synthesis process. The presence of a small ratio of polyurea components in the coating system is not detrimental to the coating performance as long as the diamine or polyamine used in the synthesis is sufficiently nonpolar and saturated to avoid degrading the moisture resistance of the system. Conceivable.

  Suitable ethylenically unsaturated oligomers include polyether urethane acrylate oligomers (CN986 available from Sartomer Company, Inc, West Chester, Pa., USA, and Bomar Specialty Co., Winstead, Connecticut, USA. BR3731, BR3741 and STC-149), tris (hydroxyethyl) isocyanurate-based acrylate oligomer, (meth) acrylated acrylic oligomer, polyester urethane acrylate oligomer (CN966 and CN973 available from Sartomer Company, Inc, and Bomar Specialty Co.) BR7432), polyureaurethane acrylate oligomers (eg, Zimmerman et al. US Pat. Nos. 4,690,502 and 4,798,852, Bishop US Pat. No. 4,609,718, and Bishop et al. Oligomers disclosed in the specification of US Pat. No. 4,629,287-each of these specifications is hereby incorporated by reference in its entirety, polyether acrylate oligomers (Rahn AG, Zurich, Switzerland) Genomer 3456), epoxy acrylate oligomer (CN120 available from Sartomer Company, Inc, and Ebecryl 3201 and 3604 available from UCB Radcure), hydrogenated polybutadiene oligomers (Echo Resins and Laboratory, Versailles, Missouri, USA) Echo Resin MBNX), and combinations thereof.

  Alternatively, the oligomer component can include a non-reactive oligomer component as described in Schissel et al. US Patent Application Publication No. 2007/0100039. This specification is hereby incorporated by reference in its entirety. These non-reactive oligomer components can be used to achieve high modulus coatings that do not become too brittle. These non-reactive oligomer materials are particularly preferred for high modulus coatings.

  The oligomeric component (s) is generally about 0% to about 90% by weight, more preferably about 25% to about 75% by weight, most preferably between about 40% and about 65% by weight. Present in the coating composition in an amount.

  The coating composition (s) can also contain one or more polymer components in place of or in combination with the oligomer component. The use of the polymer component is described, for example, in US Pat. No. 6,869,981 to Fewkes et al. This specification is hereby incorporated by reference in its entirety.

Polymers have a block copolymer and it is possible to, higher T _g than the T _g of the hard blocks is soft block comprising at least one hard block and at least one soft block. The main chain of the soft block is preferably aliphatic. Suitable aliphatic backbones include poly (butadiene), polyisoprene, polyethylene / butylene, polyethylene / propylene, and diol blocks. An example of a block copolymer is a diblock copolymer having a general structure of AB. Another example of a suitable copolymer is a triblock copolymer having the general structure ABA. The midblock has a molecular weight that is preferably at least greater than about 10,000, more preferably greater than about 20,000, even more preferably greater than about 50,000, and most preferably greater than about 100,000. For a three block copolymer (A-B-A), ( such as butadiene in the SBS copolymer as defined herein, B) intermediate block has a lower than about 20 ° C. T _g. An example of a multi-block copolymer having more than 3 blocks is thermoplastic polyurethane (TPU). TPUs are available from BASF, BFGoodrich and Bayer. The block copolymer can have any number of multiple blocks.

  The polymer component may be chemically crosslinked or may not be crosslinked when cured. The polymer is preferably a thermoplastic elastomer polymer. The polymer component preferably has at least two thermoplastic end blocks and an elastomer backbone between the two end blocks, such as a synthetic block copolymer. Suitable thermoplastic endblock materials include polystyrene and polymethylmethacrylate. Preferred intermediate blocks include ethylene propylene diene monomer (EPDM) and ethylene propylene rubber. The elastomeric intermediate block can be polybutadiene, polyisoprene, polyethylene / butylene, and polyethylene / propylene.

  Commercially available styrene block copolymers include KRATON ™ (Kraton Polymers, Austin, Texas, USA), CALPLENE ™ (Repsol Quimics SA Corporation, Spain), SOLPLENE ™ (Philips Petroleum Co.), STEARON (Trademark) (Firestone Tire & Rubber Co., Akron, Ohio, USA), a styrene-butadiene linear block copolymer, KRATON ™ D1101 (Kraton Polymers), a styrene-isoprene linear block copolymer, KRATON ™ D1193 (Kraton Polymers), approximately 2% by weight metal oxide grafted styrene-ethylene-butylene block copolymer, KRATON ™ FG1901X (Kraton Polymers), styrene-isoprene linear block copolymer KRATON ™ D1107 (Kraton Polymers) and liquid isoprene, HAR MAN ISOLENE (TM) there is (Elementis Performance Polymers, New Jersey, USA Belleville (Belleville)).

  When used, the polymer component (s) is generally from about 5% to about 90% by weight, preferably from about 10% to about 30% by weight, most preferably from about 12% by weight. Present in the coating composition in an amount up to about 20% by weight.

  The one or more monomer components are preferably ethylenically unsaturated. Suitable functional groups for the ethylenically unsaturated monomers used according to the present invention include acrylates, methacrylates, acrylamides, N-vinylamides, styrenes, vinyl ethers, acid esters and combinations thereof (for polyfunctional monomers). Is not limited. Of course, (meth) acrylate monomers are usually preferred.

  In general, low molecular weight (ie, about 120-600) liquid (meth) acrylate functional monomers are added to the formulation to provide the fluidity necessary to apply the coating composition in conventional liquid coating equipment. Added. Typical acrylate functional liquids in these systems include monofunctional acrylates and polyfunctional acrylates (ie, monomers having two or more functional groups). Examples of such polyfunctional acrylates are two functional acrylates having two functional groups, three functional acrylates having three functional groups, and four functional acrylates having four functional groups. Monofunctional methacrylates and polyfunctional methacrylates can be used together.

  If utilization of a moisture resistant component is desired, the monomer component will be selected based on compatibility with the chosen moisture resistant oligomer. Because such oligomers are highly non-polar, not all such liquid polymers can be combined with moisture resistant oligomers and copolymerized. For satisfactory coating compatibility and moisture resistance, it is desirable to use a liquid acrylate monomer component comprising a saturated predominantly aliphatic monoacrylate or diacrylate monomer or alkoxyacrylate monomer.

  Suitable polyfunctional ethylenically unsaturated monomers include ethoxylated bisphenol A diacrylates (SR349 and SR601, available from Sartomer Company, Inc, and others having a degree of ethoxylation of 2 to higher, preferably in the range of 2 to about 30. Photomer 4025 and Photomer 4028 available from Cognis Corp. of Ambler, Pennsylvania, USA) and propoxylated bisphenol A diacrylates having a propoxylation degree of 2 to higher, preferably in the range of 2 to about 30. Such as alkoxylated bisphenol A diacrylate; ethoxylated trimethylolpropane polyacrylate (Photomer 4149, available from Cognis Corp., and Sartomer Company, having a degree of ethoxylation of 3 to higher, preferably in the range of 3 to about 30. SR499 available from Inc.), with a propoxylation degree of 3 to Proxylated trimethylolpropane triacrylate (Photomer 4072 available from Cognis Corp., and SR492 available from Sartomer Company, Inc.) and ditrimethylolpropane tetraacrylate (Cognis Corp), high, preferably in the range of 3 to about 30 Alkoxylated or unmethylated methylol propane polyacrylates such as Photomer 4355 available from.; Propoxylated glyceryl triacrylates having a propoxylation degree of 3 to higher (Photomer 4096, available from Cognis Corp., and Alkoxylated glyceryl triacrylate, such as SR9020 available from Sartomer Company, Inc ,; pentaerythritol tetraacrylate (SR295 available from Sartomer Company, Inc,), ethoxylated pentaerythritol tetraacrylate (obtained from Sartomer Company, Inc, SR494) and dipentaerythritol pentaacrylate (Photomer 4399 available from Cognis Corp. and SR399 available from Sartomer Company, Inc.); Tris- (2 Of suitable sensitive isocyanurates with acrylic acid or acryloyl chloride, such as -hydroxyethyl) isocyanurate triacrylate (SR368 available from Sartomer Company, Inc.) and tris- (2-hydroxyethyl) isocyanurate diacrylate Isocyanurate polyacrylate formed by reaction; tricyclodecane dimethanol diacrylate (CD406 available from Sartomer Company, Inc.) and ethoxyl having a degree of ethoxylation of 2 to higher, preferably in the range of about 2-30. Polyethylene glycol Alcohol polyacrylates, such as diacrylates, with or without alkoxylation; epoxy acrylates formed by adding acrylates to bisphenol A diglycidyl ether or the like (Photomer 3016 available from Cognis Corp.); and dicyclo There are, but are not limited to, monocyclic or polycyclic aromatic or non-aromatic polyacrylates such as pentadiene diacrylate.

It may also be desirable to use some amount of monofunctional ethylenically unsaturated monomer that can be introduced to affect the water absorption of the cured product, adhesion to other coating materials, or behavior under stress. possible. Examples of monofunctional ethylenically unsaturated monomers include hydroxyalkyl acrylates such as 2-hydroxyethyl-acrylate, 2-hydroxypropyl-acrylate and 2-hydroxybutyl-acrylate; methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl Acrylate, butyl acrylate, amyl acrylate, isobutyl acrylate, t-butyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate (SR440 available from Sartomer Company, Inc, and Old, New Jersey, USA) Ageflex FA8 available from CPS Chemical Co. of Old Bridge), 2-ethylhexyl acrylate, nonyl acrylate Decyl acrylate, isodecyl acrylate (SR395 available from Sartomer Company, Inc, and Ageflex FA10 available from CPS Chemical Co.), undecyl acrylate, dodecyl acrylate, tridecyl acrylate (SR489 available from Sartomer Company, Inc,) , Lauryl acrylate (SR335 available from Sartomer Company, Inc., Ageflex FA12 available from CPS Chemical Co., and Photomer 4812 available from Cognis Corp.), octadecyl acrylate, and stearyl acrylate (available from Sartomer Company, Inc.) SR257) long chain and short chain alkyl acrylates; dimethylaminoethyl acrylate, diethylaminoethyl acrylate and 7-amino-3,7-dimethyloctyl acrylate, aminoalkyl acrylates; butoxyl ethyl acrylate, phenoxy Ethyl acrylate (Sartomer Company, Inc, available from SR339, CPS Chemical
Ageflex PEA available from Co., and Photomer 4035 available from Cognis Corp., phenoxyglycidyl acrylate (CN131 available from Sartomer Company, Inc,), lauryloxyglycidyl acrylate (CN130 available from Sartomer Company, Inc,) and Alkoxyalkyl acrylates such as ethoxyethoxyethyl acrylate (SR256 available from Sartomer Company, Inc.); cyclohexyl acrylate, benzyl acrylate, dicyclopentadiene acrylate, tricyclodecanyl acrylate, bornyl acrylate, isobornyl acrylate (Sartomer SR423 and SR506 available from Company, Inc, and Ageflex IBOA available from CPS Chemical Co.), tetrahydrofurfuryl acrylate (SR285 available from Sartomer Company, Inc,), caprolactone acrylate (Sartomer Company, Inc, Monocyclic and polycyclic aromatic acrylates or non-aromatic acrylates such as SR495 available from and Tone M100) available from Union Carbide Company of Dunbury, Connecticut and acryloylmorpholine; polyethylene glycol monoacrylate, Alcohol-based acrylates such as polypropylene glycol monoacrylate, methoxyethylene glycol acrylate, methoxypolypropylene glycol acrylate, methoxypolyethylene glycol acrylate, ethoxydiethylene glycol acrylate, and ethoxylated (4) nonylphenol acrylate (Photomer 4003 available from Cognis Corp. SR504) available from Sartomer Company, Inc, and propoxylated nonylphenol acrylate (from Cognis Corp. Various alkoxylated alkylphenol acrylates such as Photomer 4960) available; diacetone acrylamide, isobutoxymethyl acrylamide, N, N′-dimethyl-aminopropyl acrylamide, N, N-dimethyl acrylamide, N, N-diethyl acrylamide and acrylamides such as t-octylacrylamide; vinyl compounds such as N-vinylpyrrolidone and N-vinylcaprolactam (both available from International Specialty Products of Wayne, NJ, USA); and maleate esters and There are acid esters such as, but not limited to, fumarate esters.

  The monomer component is generally in an amount between 10% and about 90% by weight, more preferably between about 20% and about 60% by weight, and most preferably between about 25% and about 50% by weight. Exists within.

  As is well known, the optical fiber coating composition may also contain a polymerization initiator suitable for allowing the composition to polymerize (ie, cure) after application to the glass fiber. Polymerization initiators suitable for use in the primary coating composition of the present invention include thermal polymerization initiators, chemical polymerization initiators, electron beam polymerization initiators and photopolymerization initiators. A photopolymerization initiator is particularly preferred. For most acrylate-based coating formulations, conventional photoinitiators such as known ketone photoinitiators and / or phosphorylated photoinitiators are preferred. When used in the composition of the present invention, the photopolymerization initiator is present in an amount sufficient to obtain rapid UV curing. In general, sufficient amounts include from about 0.5% to about 10.0% by weight, more preferably between about 1.5% and about 7.5% by weight. If a low degree of cure is desired or no cure is required, the amount of photoinitiator used in a particular composition can be less than 0.5% by weight or omitted entirely.

When used in small amounts but effective in promoting photocuring, the photopolymerization initiator should provide a reasonable cure rate without premature gelling of the coating composition. The desired cure rate is any rate sufficient to cause substantial curing of the coating material. When measured with an irradiation dose versus elastic modulus curve, the curing rate for a coating thickness of about 25-30 μm is, for example, less than 1.0 J / cm ² , preferably less than 0.5 J / cm ² .

  Suitable photoinitiators include 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 available from Chiba Specialty Chemical, Hawthorne, NY, USA), (2,6-dimethoxybenzoyl) -2,4,4-trimethylphenyl. Phosphorus oxide (blends Irgacure 1800, 1850 and 1700 commercially available from Chiba Specialty Chemical), 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651 available from Chiba Specialty Chemical), bis (2,4,6-trimethyl) Benzoyl) phenyl-phosphorus oxide (Irgacure 819 available from Chiba Specialty Chemical), (2,4,6-trimethylbenzoyl) diphenyl-phosphorus oxide (LUCIRIN TPO available from BASF in Munich, Germany), (2, There are 4,6-trimethylbenzoyl) phenyl-phosphorus oxide (LYCILIN TPO-L available from BASF), and combinations thereof.

  The coating composition can further contain one or more additives as required. These additives include catalysts, carrier surfactants, tackifiers, fixing agents, antioxidants, stabilizers, reactive diluents, lubricants, fluorescent agents, and low molecular weight non-crosslinked resins. It is not limited. Some additives, such as catalysts, reactive surfactants and fluorescent agents, control the polymerization process and thus contribute to the physical properties (e.g. elastic modulus, glass transition temperature) of the polymer product formed from the coating composition. Can work to influence. Other additives can affect the polymer composition of the coating composition (eg, protection against depolymerization or oxidative degradation).

  An example of a catalyst is a tin catalyst that is used to catalyze the formation of urethane bonds in some oligomeric components. Regardless of whether the catalyst remains as an additive to the oligomer component or an additional amount of catalyst is incorporated into the composition of the present invention, the presence of the catalyst can serve to stabilize the oligomer component within the composition. .

  Suitable carriers, and more particularly carriers that function as reactive surfactants, include polyalkoxypolysiloxanes. Preferred carriers are available from Goldschmidt Chemical Co. (Hopewell, Vermont, USA) under the trade names TEGORAD 2200 and TEGORAD 2700 (acrylated siloxane). These reactive surfactants are preferably in an amount between about 0.01 pph and about 10 pph, more preferably between about 0.05 pph and about 5 pph, and most preferably between about 0.1 pph and about 2.5 pph. Can exist in

  Another class of suitable carriers are polyols and non-reactive surfactants. Examples of suitable polyols and non-reactive surfactants include Aclaim 3201 (ethylene oxide-propylene), a polyol available from Lyondel (formerly known as Arco Chemical) (Newtown Square, PA, USA). Oxide copolymers) and Tegoglide 435 (polyalkoxy-polysiloxane), a non-reactive surfactant available from Goldschmidt Chemical Co. The polyol or non-reactive surfactant is preferably between about 0.01 pph and about 10 pph, more preferably between about 0.05 pph and about 5 pph, most preferably between about 0.1 pph and about 2.5 pph. Can be present in quantities.

  Suitable carriers can also be amphiphilic molecules. Amphiphilic molecules have both hydrophilic and hydrophobic segments. The hydrophobic segment can instead be referred to as a lipophilic (fat / oil preference) segment. A tackifier is an example of such an amphiphilic molecule. Tackifiers are molecules that can modify the limited lifetime rheological properties of a polymer article. In general, tackifying additives will make the polymer article harder the higher the strain rate or shear rate, and the polymer article will be softer at lower strain rates or lower shear rates. Tackifiers are additives commonly used in the adhesive industry and are known to enhance the ability of a coating to form a bond of the object on which the coating is applied.

  A preferred tackifier is Uni-tac® R-40 (hereinafter referred to as 'R-40') available from International Paper Co. of Purchase, NY. R-40 is tall oil rosin having a polyether segment and is obtained from a chemical homologue of abietic acid ester. The tackifier is preferably present in the composition in an amount between about 0.01 pph and about 10 pph, more preferably between about 0.05 pph and about 5 pph. A suitable alternative tackifier is the Escorez family of hydrocarbon tackifiers available from Exxon. For further information on Escorez tackifiers, see Mao US Pat. No. 5,242,963. This specification is hereby incorporated by reference in its entirety. The carriers described above can also be used in combination.

  Any suitable fixing agent can be used. Examples of suitable fixing agents are organic functional silanes, titanates, zirconates and mixtures thereof. The fixing agent is preferably poly (alkoxy) silane, and most preferably bis (trimethoxysilylethyl) benzene. A suitable alternative fixer is 3-mercaptopropyltrimethoxysilane (3-MPTMS, available from United chemical Technologies, Bristol, Pa., USA, and also from Gelest, Morrisville, Pa.), ( There are 3-acryloxypropyltrimethoxysilane (available from Gelest), 3-methacryloxypropyltrimethoxylane (available from Gelest), and bis (trimethoxysilylethyl) benzene (available from Gelest). Other suitable fixing agents are described in US Pat. Nos. 4,921,880 and 5,188,864 to Lee et al. Each of these specifications is included herein by reference. The fixer, when present, is used in an amount between about 0.1 pph and about 10 pph, more preferably between about 0.25 pph and about 3 pph.

  Any suitable antioxidant can be used. Preferred antioxidants include bis-hindered phenol sulfide or thiodiethylene bis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamate (Irganox 1035 available from Chiba Specialty Chemical). It is not limited to. Antioxidants, if present, are used in amounts between about 0.1 pph and about 3 pph, more preferably between about 0.25 pph and about 2 pph.

  Any suitable stabilizer can be used. One preferred stabilizer is a tetrafunctional thiol, such as pentaerythritol tetrakis (3-mercaptoproprionate), available from Sigma-Aldrich (St. Louis, Mo., USA). Stabilizers, when present, are used in amounts between about 0.01 pph and about 1 pph, more preferably between about 0.01 pph and about 0.2 pph.

  Any suitable fluorescent agent can be used. Examples of fluorescent agents include Uvitex OB, 2,5-thiophenyl bis (5-ter-butyl-1,3-benzoxazole) (Chiba Specialty Chemical), Blankophor KLA available from Bayer, bisbenzoxazole compounds, phenyl There are, but are not limited to, coumarin compounds and bis (styryl) biphenyl compounds. It is desirable that the fluorescent dye be present in the composition at a concentration of from about 0.003 pph to about 0.5 pph, more preferably from about 0.005 pph to about 0.3 pph.

  As used herein, weight percent of a particular component refers to the amount incorporated into the bulk composition excluding any additives. The amount of additive incorporated into the bulk composition to make the composition of the present invention is listed in pph (per hundred percent). For example, oligomers, monomers and photoinitiators are combined to form a bulk composition such that the total weight percent of these components is equal to 100%. This bulk composition incorporates a certain amount of specific additives, for example 1 pph, exceeding 100% by weight of the bulk composition.

Returning to the coating system shown in FIG. 1 and FIG. 1, the primary coating 14 is a soft crosslink having a low Young's modulus (eg, below about 5 MPa at 25 ° C.) and a low T _g (eg, below about 10 ° C.). Preferably formed from a polymeric material. The Young's modulus of the primary coating 14 is preferably between about 0.025 MPa and about 3 MPa, more preferably between about 0.05 MPa and about 3 MPa, and between about 0.1 MPa and about 3 MPa. Even more preferred is between about 0.05 MPa and about 0.5 MPa, and most preferred is between about 0.05 MPa and about 0.3 MPa. T _g is preferably between about −100 ° C. and about −25 ° C., more preferably between about −100 ° C. and about −40 ° C., and between about −100 ° C. and about −50 ° C. Most preferably. The thickness of the primary coating is preferably less than about 25 μm, more preferably less than about 20 μm, even more preferably less than about 15 μm, and most preferably in the range of about 5 μm to about 10 μm. . The primary coating is generally applied to the glass fiber as a liquid and allowed to cure, as described in further detail herein below. There may also be various additives that enhance one or more properties of the primary coating, including antioxidants, fixing agents, carrier surfactants, tackifiers, catalysts, stabilizers, surface agents and fluorescent agents. .

  Many suitable primary coatings include, for example, US Pat. No. 6,326,416 to Chien et al., US Pat. No. 6,531,522 to Winningham et al., US Pat. No. 6,539,152 to Fuchs et al., US Pat. No. 6,563,996 to Winningham, US Pat. No. 6,869,981 to Fux et al., US Pat. Nos. 7010206 and 72221842 to Baker et al. And US Pat. No. 7,423,105 to Winningham. Each of these specifications is hereby incorporated by reference in its entirety.

  Suitable primary coating compositions include about 25% to 75% by weight of one or more urethane acrylate oligomers, about 25% to about 65% by weight of one or more monofunctional ethylenically unsaturated monomers, about 0% by weight. % To about 10% by weight of one or more polyfunctional ethylenically unsaturated monomers, about 1% to about 5% by weight of one or more photoinitiators, one of about 0.5 pph to about 1.5 pph. These antioxidants include, but are not limited to, from about 0.5 pph to about 1.5 pph of one or more fixing agents, and from 0.01 pph to about 0.5 pph of one or more stabilizers.

  Other suitable primary coating compositions include about 52 wt.% Polyether urethane acrylate (Bomar Specialty Company BR3741), between about 40 wt.% And about 45 wt.% Multifunctional acrylate monomer (Cognis Photomer 4003 or Photomer 4960), 0 to about 5% by weight of a monofunctional acrylate monomer (caprolactone acrylate or N-vinylcaprolactone), up to about 1.5% by weight of a photoinitiator (from Irgacure 819 or Irgacure184, BASF from Chiba Specialty Chemical) LUCIRIN® TPO, or combinations thereof), which includes about 1 pph fixative (3-acryloxypropyltrimethoxysilane), and about 1 pph antioxidant (Irganox 1035 from Chiba Specialty Chemical) Fluorescent agent up to about 0.05 pph (Uvitex OB from Chiba Specialty Chemical) and stabilizer up to about 0.03 pph (from Sigma-Aldrich as needed) Hand it pentaerythritol tetrakis (3-mercapto proprionate)) is added.

Examples of primary coating compositions include the following formulations:
(1) 52% by weight polyetherurethane acrylate oligomer (BR3741, Bomar Specialty), 40% by weight ethoxylated (4) nonylphenol acrylate (Photomer 4003, Cognis Corp.), 5% by weight N-vinylpyrrolidinone, 1. 5% by weight bis (2,4,6-trimethylbenzoyl) phenyl-phosphorus oxide (Irgacure 819, Chiba Specialty), 1.5% by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba Specialty), 1 pph thiol Diethylenebis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamate (Irganox 1035, Chiba Specialty), and 1 pph of 3-acryloxypropyltrimethoxysilane;
(2) 52 wt.% Polyether urethane acrylate oligomer (BR3741, Bomar Specialty), 40 wt.% Ethoxylated (4) nonylphenol acrylate (Photomer 4003, Cognis Corp.), 5 wt.% N-vinylcaprolactam, 1. 5% by weight bis (2,4,6-trimethylbenzoyl) phenyl-phosphorus oxide (Irgacure 819, Chiba Specialty), 1.5% by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba Specialty), 1 pph thiol Diethylenebis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamic ester (Irganox 1035, Chiba Spechialty) and 1 pph 3-acryloxypropyltrimethoxysilane;
(3) 52 wt% polyether urethane acrylate oligomer (BR3731, Sartomer Co.), 45 wt% ethoxylated (4) nonylphenol acrylate (SR504, Sartomer Co.), 3 wt% (2,6-dimethoxybenzoyl) ) -2,4,4-trimethylphenyl-phosphorus oxide (Irgacure 1850, Chiba Specialty), 1 pph thiodiethylenebis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamic acid ester (Irganox 1035, Chiba Specialty), 1 pph bis (trimethoxysilylethyl) benzene fixative, and 0.5 pph polyalkoxypolysiloxane carrier (Tegorad 2200, Goldschmidt); and
(4) 52 wt% polyether urethane acrylate oligomer (BR3731, Sartomer Co.), 45 wt% ethoxylated (4) nonylphenol acrylate (Photomer 4003, Cognis Corp.), 3 wt% (2,6-dimethoxy) Benzoyl) -2,4,4-trimethylphenyl-phosphorus oxide (Irgacure 1850, Chiba Specialty), 1 pph thiodiethylenebis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamic acid ester (Irganox 1035 , Chiba Specialty), 1 pph bis (trimethoxysilylethyl) benzene fixative and 0.5 pph tackifier (Unitac R-40, Union Camp);
(5) 52 wt% polyether urethane acrylate oligomer (BR3731, Sartomer Co.), 45 wt% ethoxylated nonylphenol acrylate (SR504, Sartomer Co.), and 3 wt% (2,6-dimethoxybenzoyl)- 2,4,4-trimethylphenyl-phosphorus oxide (Irgacure 1850, Chiba Specialty); and
(6) 52 wt% urethane acrylate oligomer (BR3741, Bomar), 41.5 wt% ethoxylated nonylphenol acrylate monomer (Photomer 4003, Cognis), 5 wt% caprolactone acrylate monomer (Tone M-100, Dow), 1.5 wt% Irgacure 819 photoinitiator (Chiba), 1 pph thiodiethylenebis (3,5-di-tert-butyl) -4-hydroxyhydrocinnamic acid ester (Irganox 1035, Chiba Specialty), 1 pph 3-acryloxypropyltrimethoxysilane (Gelest), and 0.032 pph pentaerythritol tetrakis (3-mercaptopropionate) (Aldrich);
However, it is not limited to these.

The material of the outer coating 18 is generally a polymerized coating composition containing a urethane acrylate liquid that, when polymerized, increases the molecular crosslinking rate. In some preferred embodiments, the outer coating is not a thermoplastic material. The outer coating 18 has a high Young's modulus (eg, greater than about 0.08 GPa at 25 ° C.) and a high T _g (eg, greater than about 50 ° C.). The Young's modulus is preferably between about 0.1 GPa and about 8 GPa, more preferably between about 0.5 GPa and about 5 GPa, and most preferably between about 0.5 GPa and about 3 GPa. . T _g is preferably between about 50 ° C. and about 120 ° C., more preferably between about 50 ° C. and about 100 ° C. The thickness of the secondary coating is less than about 40 μm, more preferably between about 20 μm and about 40 μm, and most preferably between about 20 μm and about 30 μm.

  Other materials suitable for use in the outer coating material, as well as requirements relating to the selection of such materials, are well known in the art and are described in the specifications of Chapin US Pat. Nos. 4,962,2992 and 5,104,433. Has been. Each of these specifications is hereby incorporated by reference in its entirety. Alternatives to such coatings include low oligomer content / low urethane content, as described in US Pat. No. 6,775,451 to Bothelho et al. And US Pat. No. 6,689,463 to Chou et al. High modulus coatings are also obtained using a quantity coating system. In addition, non-reactive oligomer components are used to achieve high modulus coatings, as described in Schissel et al US Patent Application Publication No. 2007/0100039. This specification is hereby incorporated by reference in its entirety. The outer layer coating is generally applied to the already coated fiber (which is either cured or not) and subsequently cured, as described in more detail below. Enhance one or more properties of the outer layer coating, including antioxidants, catalysts, lubricants, low molecular weight non-crosslinked resins, stabilizers, surfactants, surface agents, slip agents, waxes, ultra fine polytetrafluoroethylene, etc. Various additives can also be present. The secondary coating can also include ink, as is well known in the art.

  Suitable outer layer coating compositions include from about 0 to 20% by weight of one or more urethane acrylate oligomers, from about 75 to about 90% by weight of one or more monofunctional ethylenically unsaturated monomers, from about 0 to about 10% by weight. Comprising one or more multifunctional ethylenically unsaturated monomers, from about 1 to about 5 weight percent of one or more photoinitiators, and from about 0.5 to about 1.5 pph of one or more antioxidants. However, it is not limited to these.

  Other suitable outer layer coating compositions are about 10% by weight polyether urethane acrylate oligomer (Bomar Specialty KWS4131), about 72 to about 82% by weight ethoxylated (4) bisphenol A diacrylate monomer (Cognis Photomer 4028). And about 5 wt% bisphenol A diglycidyl diacrylate (Cognis Photomer 3016), optionally up to about 10 wt% diacrylate monomer (Cognis Photomer 4002) or N-vinylcaprolactam, about 3 Up to weight percent of photoinitiator (Chiba Specialty Irgacure 184 or BASF LUCIRIN TPO, or combinations thereof), including about 0.5 pph antioxidant (Chiba Specialty Irganox 1035) However, it is not limited to these.

Examples of outer layer coating compositions include the following formulations:
(1) 40% by weight urethane acrylate oligomer (CN981, Sartomer Company, Inc.), 17% by weight propoxylated (3) glyceryl triacrylate monomer (SR9030, Sartomer Inc.), 25% by weight pentaerythritol tetraacrylate (SR349, Sartomer Inc.) and 3% by weight of 1-hydroxycyclohexyl phenyl ketone / bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl-phosphate oxide blend (Irgacure 1850, Chiba Specialty) ;as well as
(2) 10% by weight of polyetherurethane acrylate (KWS4131, Bomar), 5% by weight of bisphenol A diglycidyl diacrylate (Photomer 3016, Cognis), 82% by weight of ethoxylation (4) bisphenol adiacrylate (Photomer 4028, Cognis), 1.5% by weight LUCIRIN TPO photoinitiator (BASF), 1.5% by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba), and 0.5 pph thiodiethylene (3.5- Di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty Chemical);
However, it is not limited to these.

The first intermediate coating is generally provide relatively high Young's modulus and a relatively high T _g as compared to Young's modulus and T _g of the primary coating is the polymerization product of the coating composition. The Young's modulus is preferably between about 0.1 GPa and about 2 GPa, more preferably between about 0.2 GPa and about 1 GPa, and most preferably between about 0.3 GPa and about 1 GPa. . T _g is preferably between about 0 ° C. and about 60 ° C., more preferably between about 10 ° C. and about 60 ° C., and most preferably between about 10 ° C. and about 50 ° C. . The thickness of the first intermediate coating is less than about 25 μm, more preferably less than about 20 μm, even more preferably less than about 15 μm, and most preferably in the range of about 5 μm to about 10 μm.

  The composition of the first intermediate coating can be formulated using any number of known ingredients for use in forming the outer (or secondary) coating, such as, for example, Botero Low oligomer content / low urethane content, as described in US Pat. No. 6,775,451 and US Pat. No. 6,689,463, such as Chou et al., And US Pat. Application Publication No. 2007/0100039 of Sisel et al. A quantity coating system is included. Each of these specifications is hereby incorporated by reference in its entirety. This coating can optionally include ink as is well known in the art. In some embodiments, it is preferred that the first intermediate coating omits expensive additives that are useful for modifying the properties of the cured product, such as lubricants, slip agents, and waxes.

  Suitable first intermediate coating compositions include from about 0 to 20% by weight of one or more urethane acrylate oligomers, from about 75 to about 95% by weight of one or more monofunctional ethylenically unsaturated monomers, from about 0 to about 10%. % By weight of one or more multifunctional ethylenically unsaturated monomers, about 1 to about 5% by weight of one or more photoinitiators, and about 0.5 to about 1.5 pph of one or more antioxidants. Including, but not limited to.

An example of a first intermediate coating composition is the following formulation:
(1) 10% by weight aliphatic urethane acrylate oligomer (KWS4131, Bomar Specialty Co.), 87% by weight ethoxylated (4) Bisphenol A diacrylate monomer (Photomer 4028, Cognis Corp.), 3% by weight 1- Hydroxycyclohexyl phenyl ketone / bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl-phosphate oxide blend (Irgacure 1850, Chiba Specialty), 0.5 pph thiodiethylenebis (3,5-di-) tert-butyl 4-hydroxy) hydrocinnamic ester antioxidant (Irganox 1035, Chiba Specialty Chemical), and 1 pph fixer (Ebecryl 170m UCB Radcure) with acrylate and acid functionality;
(2) 10 wt% polyether-based urethane diacrylate oligomer (BR301, Bomar Specialty Co.), 22 wt% ethoxylated (8) bisphenol adiacrylate monomer (Photomer 4025, Cognis Corp.), 65 wt% ethoxyl (4) Bisphenol A diacrylate monomer (Photomer 4028, Cognis Corp.) 3% by weight of 1-hydroxycyclohexyl phenyl ketone / bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl-phosphorylated Product blend (Irgacure 1850, Chiba Specialty), 0.5 pph thiodiethylenebis (3,5-di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty Chemical), and 1 pph A fixer (Ebecryl 170m UCB Radcure) having an acrylate functionality and an acid functionality;
(3) 10% by weight aliphatic urethane acrylate oligomer (KWS4131, Bomar Specialty Co.), 50% by weight ethoxylation (4) Bisphenol A diacrylate monomer (Photomer 4028, Cognis Corp.), 37% by weight ethoxylation (3) Bisphenol A diacrylate monomer (RCC12-984, Cognis Corp.) 3% by weight of 1-hydroxycyclohexyl phenyl ketone / bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl-phosphorylated Blend (Irgacure 1850, Chiba Specialty), 0.5 pph thiodiethylenebis (3,5-di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty Chemical);
(4) 30% by weight ethoxylated (4) Bisphenol A diacrylate monomer (SR601, Sartomer Co.), 37% by weight ethoxylated (10) Bisphenol A diacrylate monomer (SR602, Sartomer Co.), 30% by weight Ethoxylated (2) bisphenol A diacrylate monomer (SR349, Sartomer Co.) and 3% by weight of 1-hydroxycyclohexyl phenyl ketone / bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl- Phosphorus oxide blend (Irgacure 1850, Chiba Specialty);
Including, but not limited to.

The second intermediate coating 16 can be in the form of a soft cross-linked polymeric material, similar to the primary coating 14, or in the form of a coating material that is slightly cross-linked or even substantially liquid. The second intermediate coating preferably exhibits a relatively low Young's modulus and / or a relatively low T _g as compared to the Young's modulus and T _g of the first intermediate coating. For example, in one preferred embodiment, the Young's modulus of the second intermediate coating is approximately 3 orders of magnitude lower and the difference between the T _{g of} these coating materials is about 70 ° C.

  According to one embodiment, the second intermediate coating remains fairly liquid after the curing process (which cures the remaining coating). As used herein, “substantially liquid” means that the degree of cure of the coating after the curing process is less than about 70%, more preferably less than about 60%, and most preferably less than about 50%. To do. For coatings that remain fairly liquid, the crosslinking of the components within the coating composition is limited. This can be achieved through the use of non-reactive oligomer components, non-acrylate monomer components, and non-crosslinkable resins and fillers.

  Reduction of the photoinitiator reactant from the composition of the second intermediate coating can also significantly reduce the degree of cure and thus contribute to a reduction in the degree of crosslinking. In this embodiment, the photoinitiator can be reduced to less than about 5 wt%, more preferably to less than 3 wt%, and most preferably to less than about 1 wt%.

According to another embodiment, the second intermediate coating is a crosslinked coating that remains very soft. In this embodiment, the second intermediate coating is substantially the same as or lower than the Young's modulus of the primary coating, the Young's modulus and the T _{g of the} primary coating is substantially the same or even lower, T It is preferable to have _g . The Young's modulus is preferably less than about 1 MPa, more preferably between about 0.01 MPa and about 0.5 MPa, and most preferably between about 0.03 MPa and about 0.3 MPa. According to one embodiment, the Young's modulus of the second intermediate coating is at least about 30% lower, more preferably at least 40% lower, and most preferably at least about 50% lower than the Young's modulus of the primary coating. _{T g} of the second intermediate coating is preferably between about -100 ° C. and about -30 ° C., more preferably between about -100 ° C. and about -40 ° C., about -100 ° C. and about Most preferably, it is between -50 ° C.

  The thickness of the second intermediate coating is less than about 40 μm, more preferably in the range of about 20 to about 40 μm, and most preferably in the range of about 20 to about 30 μm.

  Importantly, the second intermediate coating eliminates expensive additives that are useful for modifying some properties of the cured article when used as a primary coating, such as fixers and surfactants. preferable. The composition of the second intermediate coating is less than 0.25 pph, more preferably less than 0.15 pph, most preferably less than 0.05 pph, and less than 0.25 pph, more preferably less than 0.15 pph, most preferably Contains less than 0.05 pph surfactant. Since the second intermediate coating does not contact the glass fiber, these additives can be omitted completely. According to one embodiment, the second intermediate coating is equivalent to the primary coating, but the fixing agent is completely omitted.

  One preferred class of second intermediate coating compositions that form cross-linked coatings are UV curable self-adhesive compositions as described in Fux US Pat. No. 6,869,981. This specification is hereby incorporated by reference in its entirety.

Examples of second intermediate coating compositions include the following formulations:
(1) 40 wt% nonylphenol ethoxylated monoacrylate (Ph4003, Cognis Corp.), 5 wt% neophenyl glycol propoxylated diacrylate (Ph4127, Cognis Corp.), 52 wt% polyether urethane acrylate oligomer ( BR3731, Sartomer Co.), 1.5% by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba Specialty), 1.5% by weight of bis (2,4,6-trimethylbenzoyl) phenyl-phosphorus oxide (Irgacure) 819, Chiba Specialty), 1 pph thiodiethylenebis (3,5-di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty), 1 pph 3-acryloxypropyltrimethoxysilane (Gelest), 0.3 pph 3-mercaptopropyltrimethoxysilane (Gelest), and 20 pph Sylvatac RE-40N rosin ester (Arizona Chemi) cal Company);
(2) 43 wt% nonylphenol ethoxylated monoacrylate (Ph4003, Cognis Corp.), 2 wt% neophenylglycol propoxylated diacrylate (Ph4127, Cognis Corp.), 52 wt% polyether urethane acrylate oligomer ( BR3731, Sartomer Co.), 1.5% by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba Specialty), 1.5% by weight of bis (2,4,6-trimethylbenzoyl) phenyl-phosphorus oxide (Irgacure) 819, Chiba Specialty), 1 pph thiodiethylenebis (3,5-di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty), 1 pph 3-acryloxypropyltrimethoxysilane (Gelest), and 15 pph Sylvatac RE-40N rosin ester (Arizona Chemical Company); and
(3) 30 wt% nonylphenol ethoxylated monoacrylate (Ph4003, Cognis Corp.), 15 wt% caprolactone acrylate (Tone M-100, Union Carbide), 52 wt% polyether urethane acrylate oligomer (BR3741, Sartomer Co .) 1.5% by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Chiba Specialty), 1.5% by weight of bis (2,4,6-trimethylbenzoyl) phenyl-phosphorous oxide (Irgacure 819, Chiba Specialty) ) 1 pph thiodiethylenebis (3,5-di-tert-butyl 4-hydroxy) hydrocinnamate antioxidant (Irganox 1035, Chiba Specialty), 1 pph 3-acryloxypropyltrimethoxysilane (Gelest), And 0.5 pph Sylvatac RE-10L rosin (Arizona Chemical Company);
However, it is not limited to these.

  Not only these second intermediate coating compositions, but also the primary coating composition defined above can be modified to omit the fixer, similar to the second intermediate coating composition described above.

According to one preferred embodiment of a four-layer coated optical fiber, the coating composition comprises a coating having the following composition: Young's modulus higher than the Young's modulus of the primary coating and the glass transition temperature (T _g ) of the primary coating. also have any higher or the or even first intermediate coating with one's T _g, one of the lower T _g than the T _g of the low Young's modulus than the Young's modulus of the first intermediate coating and the first intermediate coating or the second intermediate coating, and is selected to have a secondary coating, also having either a or any of the higher T _g than the T _g of the high Young's modulus than the Young's modulus of the second intermediate coating and a second intermediate coating. In this configuration, the thickness of the coating is about 1 to about 10 times the thickness of the primary coating and the primary intermediate coating, respectively, either or both of the secondary intermediate coating and secondary coating. More preferably from about 1 to about 8 times thick, most preferably from about 1 to about 6 times thick.

  Referring now to FIG. 2, an optical fiber according to a second embodiment of the present invention has a fiber 22 and three layers of coatings 24, 26 and 28 that encapsulate the fiber 22. The coating 24 is the primary (innermost layer) coating and meets the conventional purpose of the primary coating. The coating 28 is an outer coating and meets the conventional purpose of secondary coatings. There is a single intermediate layer 26 between the primary coating and the secondary coating. It is this presence of the intermediate coating that allows improved microbending performance.

  The coatings 24, 26 and 28 can generally be the same type of coating as described above with respect to the coatings 14, 16 and 18 of the first embodiment.

According to one preferred configuration of this second embodiment, the primary coating has a Young's modulus of about 0.1 to about 3 MPa and / or a glass transition temperature (T _g ) of about −100 ° C. to about −30 ° C. has, one of the intermediate coating 26 is the primary coating 24 of the Young's modulus substantially the same as or even lower Young's modulus and primary coating T _g and substantially the same or even lower T _g Or both. Secondary coating 28 are generally chosen to Young's modulus and T _g is higher than the Young's modulus and T _g of the intermediate coating.

  In one embodiment, the coating composition used to form the intermediate coating is substantially the same as the composition forming the primary coating composition, or any fixer present in the primary coating composition is the intermediate coating. A polymer of a composition that is otherwise substantially the same except that it is omitted from the composition.

  The optical fiber of the present invention can also be in the form of an optical fiber ribbon that includes a plurality of optical fibers that are encapsulated in a matrix material, aligned substantially in parallel, and substantially coplanar. An example of a ribbon configuration is shown in FIG. 3, which shows a ribbon 30 having 12 optical fibers 20 encapsulated with a matrix material 32. The matrix material can be made of a single layer or a composite structure. Suitable matrix materials include polyvinyl chloride or other thermoplastic materials, and some materials are known to be useful as secondary coating materials. In one embodiment, the matrix material can be a polymer of the composition used to form the outer layer coating.

  The optical fiber of the present invention can be made using conventional draw tower technology for making glass fiber and coating glass fiber. Briefly, the process for making a coated optical fiber according to the present invention comprises the steps of making glass fiber 12, a primary coating composition on the glass fiber, one or more intermediate coating compositions, and a secondary coating composition. And then curing all coating compositions simultaneously. This is known as a wet-on-wet process. If desired, each of the sequentially applied coating compositions can be applied to the coated fiber before or after polymerization of the underlying coating composition. Polymerization of the underlying coating composition prior to subsequent application of the coating composition is known as a wet-on-dry process. If a wet-on-dry process is used, an additional polymerization process must be used.

  The drawing of glass fibers from specially made cylindrical preforms heated locally and symmetrically, for example to a temperature of about 2000 ° C., is well known. When the preform is heated, such as by feeding the preform into the furnace and passing through the furnace, the glass fibers are drawn from the molten material. After the glass fiber has been drawn from the preform, preferably immediately after cooling, a composition of primary coating, intermediate coating and secondary coating is applied to the glass fiber. The coating composition is then cured into a coated optical fiber. Curing methods are thermally induced, chemically induced, such as by exposing the uncured coating composition on the glass fiber to heat or ultraviolet light or an electron beam, depending on the nature of the coating composition and the polymerization initiator used. Or it can be set as the method by radiation induction. It is often advantageous to apply the primary coating composition and any secondary coating composition sequentially following the drawing process. Methods for applying a two-layer coating composition to moving glass fibers are disclosed in US Pat. No. 4,474,830 to Taylor and US Pat. No. 4,851,165 to Rennell et al. Each of these specifications is hereby incorporated by reference in its entirety.

  One embodiment of a method for making a coated optical fiber according to the present invention is represented generally by the reference numeral 40 and is further illustrated in FIG. As shown, a sintered preform 42 (partially shown as a preform) is drawn into an optical fiber 44. The fiber 44 passes through the coating forming elements 46 and 48, which may comprise one or more dies that allow the application of a single layer coating composition or a multilayer coating composition, as is known in the art. To do. The die also adjusts the coating thickness to the desired dimension. Preferably, the primary coating and first intermediate coating composition is applied to the fiber 44 at element 46 and the second intermediate coating and secondary coating composition is applied to the fiber 44 at element 48. A curing element 50 is disposed downstream of the element 46, a curing element 52 is disposed downstream of the element 48, and a curing element 50 is disposed downstream of the element 46 to cure the coating composition applied to the fiber 44. Thus, the curing element 52 is disposed downstream of the element 48. Alternatively, the coating composition applied at element 46 can subsequently be cured after fiber 44 passes through element 48. A traction device 56 is used to pull the coated optical fiber 54 through the element 52.

  As will be appreciated by those skilled in the art, the system shown in FIG. 4 accepts separate or simultaneous application and curing of the coating composition by any combination of known wet-on-wet or wet-on-dry processes. Can be modified as follows. According to one approach, either or both of the primary coating composition and the first intermediate coating composition can be cured prior to application of the second intermediate coating composition and the secondary coating composition. it can. Alternatively, all four layers of the coating composition can be applied to the fiber and then cured in a single polymerization step.

  Once optical fibers or fiber ribbons according to the present invention are made, these optical fibers or fiber ribbons can be incorporated into a telecommunications system for transmission of data signals.

  The invention will be further clarified by the following examples which are intended to illustrate the invention.

Example 1-4 A standard single mode compliant optical fiber G652 with a layer coated optical fiber diameter of about 125 μm was coated with a draw tower using the composition described below. The coating composition was cured with a single actinic radiation using 6 lamps (375 W / lamp) during drawing (20 m / sec).

Test fiber 1 is a 125 μm diameter commercial glass fiber, 4 μm thick primary coating (0.170 MPa, −27 ° C. T _g ) formed using composition A (being 133 μm diameter), and 8 μm thick first formed using composition B. 1 intermediate coating (1.0 GPa, 64 ° C. T _g ) (with a diameter of 149 μm), 22 μm thick second intermediate coating (0.125 MPa, −26 ° C. T _g ) formed with composition C (with a 193 μm diameter) And a 26 μm thick outer layer coating (1.6 GPa, 68 ° C. T _g ) (with a diameter of 245 μm) formed using composition D.

Test fiber 2 is a 125 μm commercial glass fiber, a 5 μm-thick primary coating (0.125 MPa, −26 ° C. T _g ) (with a diameter of 135 μm) formed using composition C, and a 9.5 μm thickness formed using composition B. First intermediate coating (1.0 GPa, 64 ° C. T _g ) (with a diameter of 154 μm), 21 μm thick secondary coating (0.125 MPa, −26 ° C. T _g ) formed with the composition C (with a diameter of 196 μm) And a 24.5 μm thick outer layer coating (1.6 GPa, 68 ° C. T _g ) (with a diameter of 245 μm) formed using composition D.

  Composition A consists of 52% by weight urethane acrylate oligomer (GR3741, Bomar), 41.5% by weight ethoxylated nonylphenol acrylate monomer (Photomaer 4003, Cognis), 5% by weight caprolactone acrylate monomer (Tone M-100, Dow) And 1.5 wt% Irgacure 819 photoinitiator (Chiba), which includes 1 pph Irganox 1035 antioxidant (Chiba), 1 pph 3-acryloxypropyltrimethoxysilane (Galest), and 0 0.032 pph pentaerythritol tetrakis (3-mercaptopropionate) (Aldrich) was added and blended.

Composition B has an elastic modulus of 1.0 GPa and a T _{g of} 64 ° C. based on tan δ peak identification as measured by dynamic mechanical analysis of a 75 μm thick film cured at 1.0 J / cm ² using a Fusion D bulb. Is a commercially available outer layer (secondary) coating formulation.

  Composition D consists of 10 wt% polyether urethane acrylate (KWS4131, Bomar), 5 wt% bisphenol A diglycidyl diacrylate (Photomer 3016, Cognis), 82 wt% ethoxylated (4) bisphenol A diacrylate (Photomer) 4028, Cognis), 1.5 wt% LUCIRIN TPO photoinitiator (BASF), and 1.5 wt% Irgacure 184 photoinitiator (Chiba), to which 0.5 pph Irganox 1035 oxidation An inhibitor (Chiba) was added and blended.

  Later, the optical fiber was wound on a spool and tested for microbending.

Example 2-4 Simulation test of fiber displacement in a layer-coated optical fiber The effect of a four-layer coating system on fiber core displacement was theoretically evaluated. In the model, a short fiber (0.2 cm) is fastened at both ends and the midpoint is bent upward with a constant force. The size of the core displacement is evaluated using 3D finite element analysis. The magnitude of the core displacement generally depends on the applied force and the modulus and thickness of each layer. This assessment is significant because the predicted core displacement should correlate with the microbending loss.

  FIG. 5 is a graph showing the predicted relative displacement of the core of a commercially available compliant optical fiber G652 having two two-layer coatings versus a fiber having a four-layer coating system. The primary coating thickness varies along the x-axis and the fiber profile is 244 μm. As shown, under a constant load of about 9400 dynes (0.094 N), the estimated core displacement in a two-layer coated fiber should be significantly greater than the core displacement in a four-layer coated system. Unlike the two-layer coating system, which gives little flexibility to the primary coating dimensions, the second intermediate coating dimensions are easily controlled to minimize core displacement (and maximize microbending resistance). Can do. Theoretically, in a modeled system, the core displacement should be reduced by cooperation between the four layers of coating.

  That is, the four-layer coating of the present invention should be superior to the conventional two-layer coating in microbending performance.

Example 3-Measurement of attenuation loss of test fibers 1 and 2 Fibers 1 and 2 were subjected to a basket weave test for microbending loss. The optical fiber was loosely wound under low tension in a basket weave pattern and then rewinded at high tension. The basket weave winding pattern is one of the winding patterns where there are several fiber intersections for each convolution. Attenuation losses at 1310 nm, 1550 nm, and 1625 nm were measured after temperature cycling of the optical fiber at various temperatures between −60 ° C. and 70 ° C.

  The initial temperature cycling resulted in high losses before reaching 70 ° C. This is believed to be the result of coating defects after initial curing. However, 70 ° C. soaking appeared to heal these defects, and the subsequent decay was greatly improved even at −60 ° C. This result showed that both test fibers 1 and 2 showed improved microbending performance at 1625 nm compared to the commercially available coated fiber, but the losses at 1310 nm and 1550 nm were comparable to the control fiber. (FIGS. 6 and 7). That is, it is believed that the four-layer coating system exhibits improved microbending performance and further improvements can be achieved by optimizing the coating combination.

Example 4 Evaluation of Core Displacement After Measurement of Microbending Loss by Wire Mesh Drum Test Samples of four-layer coated optical fibers (test fibers 1 and 2) and standard two-layer coated optical fibers were evaluated using the wire mesh drum test. did. In this test, the loss of a 750 m fiber was measured three times on a tensionless drum with a large diameter and a smooth surface. The fiber was then wound under tension (eg 80 g or 100 g) on an aluminum drum covered with a wire mesh and again the loss was measured three times. The difference between the average damping while under no tension and the average damping while under tension is the calculated microbending loss.

  In theory, the microbending loss of coated optical fiber is described by Gloge, “Optical Fiber Packaging and its Influence on Fiber Straightness and Loss”, Bell As shown in System Technical Journal, 1975, Vol. 54, No. 2, p.245, it is proportional to the displacement of the core. This document is incorporated herein by reference in its entirety. Displacement is subsequently related to the mechanical properties of the fiber and coating relative to the applied force and to the roughness of the surface against which the fiber is pressed. The displacement is estimated by a finite element solution under the assumption that a constant force is applied to the midpoint of a known length of fiber. Approximate calculation of core displacement is by Baldauf et al. “Relationship of Mechanical Characteristics of Dual Coated Single Mode Optical Fibers and Microbending Loss” IEICE Tans. Commun., 1993, E76-B (4), p.352-357. This document is incorporated herein by reference in its entirety.

The additional loss measured for several differently coated optical fibers wound at 100 g tension was compared to the predicted value of the core displacement model. The core displacement parameters were evaluated using the elastic modulus and thickness of the four coating layers defined in Example 1 above. The core displacement parameters of the two-layer coated fiber were evaluated using the elastic modulus and thickness presented in Table 1 below.

  The loss expressed in dB / km is a logarithmic function of displacement. This establishes a linear relationship between loss and displacement since dB is a logarithmic measure. As shown in FIG. 8, both four-layer coated fibers (test fibers 1 and 2) are below the curve. This appears to be the result of a poorly cured third layer because the coating is applied in two stages and the third layer is only exposed in half of the lamps of the first and second layers. The reduced loss again indicates that the second intermediate layer with a very low modulus yields greatly improved microbending performance.

Example 5-3 Fabrication of a Layer-Coated Optical Fiber An optical fiber of the type shown in FIG. 2 was fabricated using a primary coating and an intermediate coating that were equivalent except that the fixer was omitted from the intermediate coating. .

  52 wt. & Polyurethane acrylate oligomer (BR3741, Bomar Spechalty), 40 wt.% Ethoxylated (4) nonylphenol acrylate (Photomer 4002, Cognis Corp.), 5 wt.% For both primary and intermediate coating formulations N-vinylpyrrolidinone, 1.5% by weight of bis (2,4,6-trimethylbenzoyl) phenyl-phosphorous oxide (Irgacure 810, Chiba Specialty), and 1 pph thiodiethylenebis (3,5-di-tert- Butyl) -4-hydroxyhydro transdermal acid salt (Irgabox 1035, Chiba Specialty) was included. The primary coating formulation also included 1 pph of 3-acryloxypropyltrimethoxysilane, but not the intermediate coating.

  Fibers 3 were made using these primary and intermediate coating formulations and the total diameter was adjusted to 190 μm during drawing. The thickness of the primary coating was about 7.5 μm and the thickness of the intermediate coating was about 25 μm.

  Two bilayer coated control fibers were made. Control fiber 5 is the same primary coating formulation used for test fiber 3 except that the thickness of the primary coating was adjusted to a total diameter of 190 μm during drawing (to about 32.5 μm thickness). It was produced using. Control fiber 6 uses the same intermediate coating formulation used for the test fiber, except that the thickness of the intermediate coating was adjusted to a total diameter of 190 μm during drawing (about 32.5 μm thick). (As primary coating formulation).

All three fibers, the coating is obtained having a Young's modulus and 65 ° C. T _g of the 1.642MPa, was prepared using the same secondary coating formulation. The thickness of the secondary coating formulation was adjusted so that the total fiber diameter was 245 μm during drawing.

  Test fiber 3 uses a wet-on-wet method so that the intermediate coating formulation is applied over the primary coating formulation layer while the primary coating formulation is still in liquid form (not cured). Produced. This was accomplished using a wet-on-wet coater block where two layers of coating were applied sequentially on the same block. The primary coating formulation containing the fixer was placed in the upper chamber of the coater block and the intermediate coating formulation was placed in the lower chamber. Both layers were cured as a whole with a UV light train and then a secondary coating formulation was applied and cured.

  Control fibers 5 and 6 were made using a wet-on-dry method in which each layer applied to the glass fiber was cured prior to application of the secondary coating formulation.

  Later, all three optical fibers were wound on a spool and tested for fine delamination.

Example 6- Three Layer Coated Optical Fiber Fine Delamination Test Test Fiber 3 and control fibers 5 and 6 were subjected to a fine delamination test. For each, the loosely wound fiber was immersed in a water bath at room temperature or 65 ° C. for 30 days. The fiber was removed from the water bath, water was removed with blotting paper, and any delamination sites at the glass-primary coating interface were repeatedly examined under the microscope.

  Neither the test fiber 3 nor the control fiber 5 showed any signs of delamination at room temperature or 65 ° C. for 30 days. Control fiber 6, which did not contain any fixer in the primary coating formulation, showed severe delamination. This confirms that there is no difference in the water resistance performance of the adhesion between the three-layer coated fiber and the two-layer coated fiber of the present invention. Used per unit length by limiting the primary coating (containing the fixing agent) to the thin film applied directly to the glass fiber and using an intermediate coating with matching properties (but no fixing agent) A considerable reduction in the amount of fixing agent can be achieved. This translates into a lower cost to fiber production and should not have any detrimental effect on fiber performance.

  While preferred embodiments have been shown and described in detail herein, it will be apparent to those skilled in the art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention. Accordingly, such modifications, additions, substitutions, etc. are considered to be within the scope of the invention as defined in the appended claims.

10, 20 Optical fiber 12, 22 Fiber 14, 24 Primary (innermost layer) coating 15 First intermediate coating 16 Second intermediate coating 18, 28 Secondary (outer layer) coating 26 Intermediate coating 30 Optical fiber ribbon 32 Matrix material

Claims (9)

In optical fiber,
Three or more layers including glass fiber, and three or more layers enclosing the glass fiber, including a primary coating contacting the glass fiber, an intermediate coating surrounding the primary coating, and an outer coating surrounding the intermediate coating Coating,
Have
The primary coating has a Young's modulus of about 0.1 to about 3 MPa and / or a glass transition temperature (T _g ) of about −100 ° C. to about −25 ° C., and the intermediate coating has the Young's modulus of the primary coating Or have a lower Young's modulus and substantially the same as the T _{g of the} primary coating, or have either or both of a lower T _g ,
An optical fiber, wherein the optical fiber has a diameter of less than about 300 μm. Wherein the intermediate coating, the optical fiber according to claim 1, characterized in that it comprises also one about 0.2MPa lower Young's modulus and about -100 ° C. or any of about -25 ° C. T _g of the. The outer layer coating, an optical fiber according to claim 1, characterized in that it comprises also one from about 0.5 to about Young's modulus of 8.0GPa and about 50 ° C. or any of about 120 ° C. T _g of the .   The optical fiber of claim 1, wherein the primary coating has a thickness of less than about 15 m.   The optical fiber of claim 1, wherein the intermediate coating has a thickness of less than about 15 m. In optical fiber,
A glass fiber, and a coating of at least four layers enclosing the glass fiber, the primary coating contacting the glass fiber, a first intermediate coating surrounding the primary coating, and a second intermediate coating surrounding the first intermediate coating And at least four layers of coatings, including an outer layer coating surrounding the second intermediate coating,
Have
Wherein the first intermediate coating, may have any one of the primary coating of the Young's high Young's modulus than the modulus and the primary coating of the glass transition temperature (T _g) higher than T _g or,
The second intermediate coating, or may have any in any one of the T is lower than _g T _g of said lower than the Young's modulus Young's modulus of the first intermediate coating and said first intermediate coating,
The outer layer coating, or may have any in any of said T is higher than _g T _g of the said higher than the Young's modulus Young's modulus of the second intermediate coating and said second intermediate coating,
An optical fiber, wherein the optical fiber has a diameter of less than about 300 μm. The second intermediate coating is substantially the same as the Young's modulus of the primary coating or a lower Young's modulus and the T _{g of the} primary coating is substantially the same or lower. The optical fiber according to claim 6, which has any one or both of _g . The primary coating is, the optical fiber according to claim 6, characterized in that it comprises also one from about 0.1 to about Young's modulus of 3MPa and about -100 ° C. or any of about -25 ° C. T _g of the . Wherein the first intermediate coating is from about 0.1 to claim 8, characterized in that also have any of about 2.0GPa Young's modulus and about 0 ℃ or any of about 60 ° C. T _g of of Optical fiber.

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